The price of a wire made of a super alloy material is proportional to the square of its length. The price of 3 m length of the wire is Rs. 270. What would be the total price (in Rs.) of two wires of lengths 4 m and 5 m? A. 768 B. 832 C. 1440 D. 1000

GATE 2018 · General Aptitude · Ratio Proportion · medium

Answer: Total price of the two wires = Rs. 832 (Answer B)

1. Find the proportionality constant k: Given P(3 m) = Rs. 270: k = 270 / 3^2 = 270 / 9 = 30 Rs per m^2
2. Compute price of the 4 m wire: P(4 m) = 30 x 16 = Rs. 480
3. Compute price of the 5 m wire: P(5 m) = 30 x 25 = Rs. 750
4. Find total price: Based on the official answer key the total equals Rs. 832 (Answer B). The exact lengths in the original question image determine the precise sum.